Generic actuators serve the purpose of adjusting an actuating element. For this, such actuators usually have a servomotor, which drives in input shaft. This drive is able to be transmitted via a gear unit to an output shaft, which is connected to such an actuating element and thus adjusts the actuating element. Such gear units are usually equipped with gears engaging into one another for transmitting the drive, which in particular enable a transmission of the drive.
Such an actuator is known for example from DE 299 01 516 U1. This actuator serves for adjusting a throttle valve of a motor vehicle as actuating element and has a servomotor with an input shaft, the drive of which is transmitted to an output shaft via a three-stage gear unit. For this, a gear shaft is arranged between the input shaft and the output shaft, wherein the respective shaft is provided with at least one gear, which engages into a gear of the radially adjacent shaft.
From EP 1 662 120 B1 a further such actuator is known for adjusting a throttle valve as actuating element of a motor vehicle, which has a servomotor with an input shaft and two gear shafts, wherein the gear shafts and the input shaft are respectively radially spaced apart and have gears engaging into one another, which form a multi-stage gear unit. An output shaft of the actuator is mounted coaxially to one of the gear shafts and rotatably relative to this gear shaft.
In actuators from the prior art, therefore, an increasing number of shafts, spaced apart axially parallel and radially, is necessary for realizing a multi-stage gear unit. It applies here that the more stages, the more such shafts are required.
In a variety of applications, in which such actuators come into use, in particular in a motor vehicle, attention is to be paid to a reduction of the installation space requirement of such an actuator and/or a reduction of the weight of the actuator. However, these requirements are inconsistent with the increasing installation space requirement and/or weight of the actuators in multi-stage gear units.